Hygiene Sampling and Personal Protection

The reader should note that there are a number of important terms that should be committed to memory. These terms include important properties of general classes of chemicals and of a few commonly used industrial chemicals. This section will attempt to familiarize the reader with the main points. This section is not intended for practicing industrial chemists, nor is it intended as anything other than a refresher for those with strong backgrounds in chemistry. It is intended to provide a brief introduction to chemistry for the safety manager who must, as a part of his responsibilities, deal with hazardous materials issues. 

Physical State at 20 C — the physical nature of the chemical (solid, liquid, or gas) at 20°C (i.e., room temperature). Changing the temperature may alter the physical state, depending on the magnitude and direction of the change relative to the melting and boiling points of the chemical. 

Octanol/water partition coefficient (K,.) other solvents) 

Boiling Point (BP) — the temperature at which a liquid changes to gas under standard atmospheric pressure (760 mm mercury). The BP of water is 100°C, while the BPs of ethyl alcohol and n-hexane are 78.4 C and 68.7°C, respectively. Lowering the atmosi eric pressure (e.g., by aiplying a vacuum) will lower the BP conversely, higher pressures result in elevated boiling points. 

Melting Point (MP) — the temperature at which a solid changes to a liquid. The melting point is not particularly sensitive to atmospheric pressure, but it is responsive to dissolved salts which depress the melting point. Thus, in winter, it is usual to salt sidewalks to keep water from freezing. 

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Industrial Hygiene Sampling and Personal Protection Table 22. Continued. 

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